As many of you Scrabble aficionados know, proper nouns are not allowed in Scrabble. What might come as a surprise however is that chemical elements (molybdenum, uranium, oxygen) are not proper nouns. In fact, words like these are referred to by Willy van Langendonck* as appellative mass nouns meaning common nouns that can be measured without unit specification (ex. money).
This means that you can use the names of elements in Scrabble. If someone has the word SCAN on the board, then heck yes you should proudly add DIUM at the end. In fact, go one step further and feel confident in pluralizing it and taking that triple word score. Take that triple word score and take the lead. And if someone calls you on it, then you raise your chin high, get yourself over to Scrabble.com, and as you type SCANDIUMS into their online dictionary, breath calm because you will win this fight. You will win this game!
Periodic Table + Scrabble = Awesome